Nozzle arrangements and method for cleaning filter elements

ABSTRACT

A method of cleaning a filter element includes directing a jet of pressurized gas from a nozzle onto a filter element, with the jet having a non-round cross-sectional shape that is a same general cross-sectional shape as the opening in a tube sheet holding the filter element. The nozzle has a channel for the pressurized gas that is obstruction-free.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/947,873, filed Jul. 22, 2013; which is a divisional of U.S. patentapplication Ser. No. 13/292,588, filed Nov. 9, 2011, now U.S. Pat. No.8,491,708; which is a divisional of U.S. patent application Ser. No.11/946,951, filed Nov. 29, 2007, now U.S. Pat. No. 8,075,648, which is autility application of U.S. Provisional Patent Application Ser. No.60/867,844, filed Nov. 30, 2006, and which applications are herebyincorporated by reference in their entireties.

TECHNICAL FIELD

This disclosure relates to methods for cleaning filter elementsutilizing pressurized gas generators, including nozzle arrangementsdesigned to produce predetermined pulse shapes.

BACKGROUND

Dust collector devices sometimes use exhaust gas from a valve andpressure tank (reservoir) to back flush filters. Examples of such airfilter assemblies are disclosed in, for example, U.S. Pat. Nos.6,090,173; 4,218,227; 4,395,269; and patent application publication U.S.2006/0112667 A1, each of these patent documents being incorporated byreference herein.

Proper and effective cleaning of these filters requires that the exhaustjet fill the opening of the filter to be cleaned. In manyimplementations, the opening of the filter corresponds to the opening inthe tubesheet, in which the filter is mounted. This exhaust jet isnaturally round and will effectively fill a round opening. The problemof filling a filter opening (or tubesheet opening, in which the filteris mounted) that has any shape other than round has been addressed inthe past by placing a device in the direct path of the jet. Placing ajet in this location consumes a portion of the energy of the jet, causesturbulence, increases noise level, and only changes the shape of the jetfor a small fraction of the pulse duration. These factors all contributeto poor cleaning effectiveness. Improvements are desirable.

SUMMARY

A method and arrangement is provided to effectively cover, with a shapedpulse, an oval, rectangular, triangular, and other non-round shapedtubesheet opening to clean most any filter of similar geometryincluding, for example, V-pack, tubular mini-V-pack, envelope bag,hemispherical, Z, panel, etc.

A method of cleaning a filter element includes directing a jet ofpressurized gas from a nozzle onto a filter element. The jet has anon-round cross-sectional shape. The jet has a non-round cross-sectionalshape that is the same general shape as a non-round shape of an openingin a tubesheet holding a filter element. The filter element can be anytype of filter element that covers the opening in the tubesheet. Thenozzle has a channel for the pressurized gas that is obstruction-free.

A method of designing a nozzle arrangement for directing a jet ofpressurized gas into a non-round opening in a tubesheet with a non-roundfilter element is provided. The filter element can be either a tubularelement having an open interior with a non-round cross-section; a panelelement having a non-round face; a V-pack; an envelope bag; a Z-filter;a hemispherical; or any element having a non-round cross-section. Themethod includes designing a nozzle arrangement to generate a jet ofpressurized gas having a cross-sectional shape that is non-round and asame general shape as a non-round opening in a tubesheet. The nozzlearrangement includes at least one nozzle, each nozzle has anunobstructed flow channel, and each nozzle is cylindrical in shape andhas at least one open slot.

In another aspect, a pressurized gas generator is provided. Thepressurized gas generator includes a compressed air manifold storingpressurized gas, a valve in fluid communication with the manifold, and anozzle arrangement. The nozzle arrangement includes at least a singlenozzle connected to the valve. Each nozzle has a tubular wall anddefines an interior channel. The interior channel is obstruction-free.The tubular wall defines at least one open slot. In some embodiments,the tubular wall is cylindrical. In other embodiments, the tubular wallis lobed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevational view, partially broken away, of oneembodiment of an air filter system utilizing pressurized gas to cleanthe filters;

FIG. 2 is a perspective view of an example filter element having anon-round open interior which can be used in the system of FIG. 1;

FIG. 3 is a perspective view of a pressurized gas generator including acompressed air manifold, a valve, a nozzle arrangement, and a schematicdepiction of a non-round aperture of a filter;

FIG. 4 is a perspective view of a nozzle utilized in the system of FIG.3;

FIG. 4A is a perspective view of a variation of the nozzle illustratedin FIG. 4;

FIG. 5 is a perspective view of another embodiment of a nozzle that canbe utilized in the arrangement of FIG. 3;

FIG. 6 is a perspective view of another embodiment of a pressurized gasgenerator and schematic view of an aperture of a filter element;

FIG. 7 is a perspective view of a nozzle arrangement utilized in theembodiment of FIG. 6;

FIG. 8 is a perspective view of another embodiment of a nozzlearrangement that can be utilized in the system of FIG. 9 and FIG. 16;

FIG. 9 is a perspective view of another embodiment of a pressurized gasgenerator and schematic view of an aperture of a filter element;

FIG. 10 is a perspective view of another embodiment of a pressurized gasgenerator and schematic view of an aperture of a filter element;

FIG. 11 is a perspective view of a nozzle arrangement utilized in thesystem of FIG. 10 and FIG. 17;

FIG. 12 is a perspective view of another embodiment of a nozzlearrangement that can be utilized in the system of FIG. 13 and FIG. 18;

FIG. 13 is a perspective view of another embodiment of a pressurized gasgenerator and a schematic view of an aperture of a filter element;

FIG. 14 is a perspective view of another embodiment of a pressurized gasgenerator and a schematic view of an aperture of a filter element;

FIG. 15 is a perspective view of another embodiment of a nozzlearrangement that can be utilized in the system of FIGS. 13, 14, and 18;

FIG. 16 is a perspective view of a tubesheet and panel filterarrangement that is usable with the nozzle arrangements of FIGS. 4 and5;

FIG. 17 is a perspective view of a tubesheet and panel filterarrangement that is usable with the nozzle arrangements of FIGS. 8 and11;

FIG. 18 is a perspective view of a tubesheet and panel filterarrangement that is usable with the nozzle arrangements of FIGS. 12 and15; and

FIG. 19 is a perspective view of an embodiment of a lobed nozzlearrangement that can be utilized in the system of FIGS. 13, 14, and 18.

DETAILED DESCRIPTION

An air filtration system or assembly is depicted generally at 10 inFIG. 1. The system depicted includes a side wall panel 17 being brokenaway to illustrate the arrangement of various portions of the assembly.An upper wall panel 16 has an inner wall surface 19. In this embodiment,an air inlet 20 is positioned in the upper wall panel 16 so thatparticulate-ladened air or other fluid is introduced into an unfilteredfluid chamber 22. The unfiltered fluid chamber 22 is defined by a door13, the upper wall panel 16, two pair of opposing side wall panels 17,stepped wall structure or baffle arrangement 28, and a pair of slopingsurfaces 23, 24. In this embodiment, the sloping surfaces 23, 24partially define a collection area or hopper 25 within a base portion ofthe assembly. A bottom base panel or frame 26 is sealed to the side wallpanels 17 in a suitable manner.

Secured to a structural frame member 27 along each of the side wallpanels 17 is baffle member, spacer wall, or tubesheet structure 28, asmentioned above. In this embodiment, the tubesheet 28 has a step-likedesign to which are mounted individual filter elements 32. The tubesheetstructure 28 is preferably sealed on all sides to effectively seal theunfiltered fluid chamber 22 from a filtered fluid chamber 60. In thisembodiment, the structure 28 has three steps, with each step includingan upwardly extending back member 30 and a leg member 31 extending atright angles therefrom.

In the embodiment shown, the filter elements 32 are mounted to thestepped, tubesheet structure 28, so that the filter elements 32 aremounted in the unfiltered air chamber 22 in a stepped or spaced apartoverlapping relationship, and in this embodiment, in a generallydownward direction at an acute angle of inclination with respect to ahorizontal plane of the upper surface panel 16. In this manner, adistribution space 33 is defined in the uppermost portion of the filterassembly 10 by an inclined baffle 50, the side wall panels 17, the upperwall panel inner surface 19, and front access door 13. As unclean fluidenters the assembly 10 from the inlet 20, it is received into thedistribution space 33 prior to being filtered.

Individual tubular filter elements 32, as used in this disclosure, willhave non-round open filter interiors 70. As used herein, the term“tubular filter element” means that the element has filter media thatcircumscribes an interior volume. In those arrangements, the airflowturns a corner during the filtration process. For forward flow systems,the air flows from a region outside of the element, through the media,into the interior volume, and then turns a corner to exit the interiorvolume through an opening in one of the end caps. In reverse-flowsystems, the air travel is the reverse of forward flow. In theembodiment of FIG. 2, the open filter interior 70 is oval in shape. Thefilter element 32, in the embodiment of FIG. 2, has a first end cap 72and an opposite, second end cap 74. An extension of pleated media 76extends between the end caps 72 and 74. An axial gasket 78 projects fromthe first end cap 72, such that it can be compressed to form an axialseal with the tubesheet 28.

Individual panel filter elements 35 (FIGS. 16-18), as used in thisdisclosure, will have non-round filter faces and will accommodatestraight-through flow. That is, the air will not have to turn a cornerduring the filtration process. In FIG. 16, the filter media 37 isZ-media, while in FIGS. 17 and 18, the filter media 39 is pleated media.By Z-media, it is meant media as described in, for example, U.S. Pat.Publication No. 2006/0112667 A1; U.S. Pat. No. 6,190,432; and U.S. Pat.No. 6,348,085, each incorporated herein by reference. Panel filterelements of Z-media, as depicted in FIG. 16 generally have oppositefirst and second ends; with the media comprising a plurality flutes;each of the flutes having a first end portion adjacent to the filterelement first end, and a second end portion adjacent to the filterelement second end; selected ones of the flutes being open at the firstend portion and closed at the second end portion; and selected ones ofthe flutes being closed at the first end portion and open at the secondend portion.

In reference again to FIG. 1, a system for cleaning each filter element32 is provided. In the embodiment shown, the system includes a pluralityof valves 65 positioned within filtered fluid chamber 60 and directly inline with an outlet opening in the tubesheet structure 28 so as todirect a jet of compressed air into the open interior 70.

In operation, fluid, such as air, to be filtered flows into the airfiltration system 10 through the inlet 20. From there, it flows throughthe filter elements 32. The filter media 76 removes particulate materialfrom the fluid. The filtered fluid flows into the open filter interior70, through the holes in the tubesheet 28, and into the filtered fluidchamber 60. From there, the clean air flows through an outlet 64.Periodically, the filter elements 32 will be cleaned by pulsing a jet ofair from the downstream side of the media 76 to the upstream side of themedia 76. Specifically, a jet of pressurized gas will be directedthrough each of the valves 65. This will direct the jet through eachopening in the tubesheet 28 and into the open filter interior 70. Thejet of pressurized gas then flows through the media 76 from thedownstream side to the upstream side. This helps to knock debris andparticulate from the upstream side of the filter media 76, directing itto the hopper 17.

FIGS. 3-18 show various pressurized gas generators and nozzlearrangements for use with, for example, air filter assembly 10. In FIG.3, a first embodiment of a pressurized gas generator is depicted at 80.The pressurized gas generator 80 includes a compressed air manifold 82storing pressurized gas. Valve 65, as shown in FIG. 1, is depicted inFIG. 3 in fluid communication with the manifold 82. A nozzle arrangement84 is depicted connected to the valve 65. In the embodiment of FIG. 3,the nozzle arrangement 84 includes a single nozzle 86. The nozzle 86 hasa tubular wall 88, and in the particular embodiment illustrated, iscylindrical which defines an interior channel 90. The interior channel90 is obstruction-free. In other words, there are no splitters,obstructions, projections, or other materials within the channel 90 toalter the flow path of the pressurized jet. The obstruction-free channel90 results in less turbulence, less noise, and a better use of theenergy of the pressurized jet than in systems that have splitters orother obstructions within the channel 90.

In the embodiment of FIG. 3, the tubular wall 88 has a free end 92.Extending from the free end 92 is at least one open slot 94. In theembodiment of FIG. 3, there are two open slots 94. In this embodiment,the two slots 94 are spaced evenly from each other, about 180° apart (atthe 12 o'clock and 6 o'clock position). Each slot extends less than 5times the hydraulic diameter of the free end 92 of the nozzle 80,typically less than 2 hydraulic diameters of the free end 92 of thelength of the nozzle 80, and in the embodiment shown, is about 1-1.5times the hydraulic diameter of the overall length of the nozzle 80. Thenozzle 80, including the location and geometry of the slots 94, isadjusted in order to shape the pulse of the pressurized jet. The shapeof the pressurized jet is designed to be the same shape as the opening100 of a tubesheet, which may also match the cross-section of theinterior 70 of the filter element 32. Aperture 100 is schematicallyshown in FIG. 3 at 100 to illustrate an example cross-sectional shape ofopen filter interior 70 of filter element 32. The nozzle 88, includingthe obstruction-free channel 90 and slots 94 will generate a jet ofpressurized gas having a cross-sectional shape that matches the shape ofthe aperture 100. In the embodiment of FIGS. 3 and 16, the shape of theaperture 100 is oval, and is generally the same shape as: (i) thecross-sectional shape of the oval filter element 32 shown in FIG. 2; and(ii) the shape of the face of the panel filter 35 of FIG. 16.

FIG. 4 is an enlarged perspective view of the nozzle 86 shown in FIG. 3.FIG. 4A shows a perspective view of an alternate embodiment of thenozzle 86 of FIG. 4. In FIG. 4A, the nozzle 86′ shows a single slot 94defined by nozzle 88. An oval pulse shape can be generated from theembodiment of nozzle 86′ by using the single slot 94, but it ispreferred to use the two slot embodiment of nozzle 86 of FIG. 4. FIG. 5illustrates another embodiment of a nozzle at 102, which also can beused to generate an oval shaped pulse. In the embodiment of FIG. 5, thenozzle 102 includes four slots 104. In the embodiment shown in FIG. 5,the slots 104 include two slots adjacent to each other separated by astrip 106, and another two slots 104 adjacent to each other andseparated by a strip 108. The strips 106 and 108 are opposing eachother, and are at, generally, the 12 o'clock and 6 o'clock position. Theslot pairs are generally opposing each other, with the first slot pairbeing at the 11 o'clock and 1 o'clock position, and the second slot pairbeing at the 5 o'clock and 7 o'clock position.

FIG. 6 illustrates pressure gas generator 80 with nozzle arrangement 84,and in this embodiment, a pair of nozzles 110, 112. An enlarged view ofnozzles 110, 112 is illustrated in FIG. 7. The nozzles 110, 112 areformed from open tubular members 114, 115 that are angled relative toeach other. In the embodiment shown, the tubular members 114, 115 forman acute angle with respect to each other. In the particular embodimentillustrated, the tubular members 114, 115 are angled less than 45°relative to each other. Each of the nozzles 110, 112 have open slots116, 117, respectively.

The slots 116 are spaced approximately 180° apart, at the 12 o'clock and6 o'clock positions. Likewise, the slots 117 are spaced 180° apart fromeach other, at approximately the 12 o'clock and 6 o'clock position. Thenozzle arrangement 84 of FIGS. 6 and 7 can be used to generate an ovalpulse shape to fill oval aperture 118 of FIG. 6. The aperture 118 ismore elongated than the aperture 100 of FIG. 3.

FIGS. 8 and 9 show another embodiment of nozzle arrangement 84. In thisembodiment, there are three nozzles 120, 121, and 122. The three nozzles120, 121, and 122 are angled with respect to each other, with eachnozzle forming, in the embodiment shown, an acute angle with respect tothe other two nozzles. In this embodiment, each nozzle 120, 121, and 122has a single open slot 124, 125, and 126, respectively. As can be seenin FIG. 9, each of the slots 124, 125, 126 is located so that they arepointing away from adjacent respective nozzles 120, 121, 122. In otherwords, slot 126 is oriented so that it faces away from nozzle 121 andnozzle 120. Similarly, slot 124 is oriented so that it faces away fromnozzle 121 and nozzle 122. Likewise, slot 125 is oriented to face awayfrom nozzle 120 and 122.

The arrangement of FIGS. 8 and 9 results in a generally triangle shapedpulse to fill a generally triangle-shaped aperture 128. As can be seenin FIGS. 9 and 17, the aperture 128 is generally triangle but withrounded corners rather than sharp points at the corners.

Another embodiment of a nozzle arrangement 84 that can be used togenerate a triangle shaped pulse into generally triangular-shapedaperture 128 is illustrated in FIGS. 10 and 11. Nozzle 130, in thisembodiment, is a single nozzle and defines three slots 132. The slots132 are equally spaced relative to each other about the circumference ofthe nozzle 130. In this embodiment, the slots 132 are spaced about 60°apart, at the 12 o'clock, 4 o'clock and 8 o'clock positions. Anotherembodiment of a nozzle arrangement 84 is illustrated in FIGS. 12 and 13.In this embodiment, the nozzle arrangement 84 includes four nozzles 134,135, 136, and 137. Each of the nozzles is angled with respect to anadjacent nozzle acutely, to form two opposing pairs of nozzles. Forexample, nozzles 135 and 137 are opposed to each other, and angled about180° apart, while nozzles 134 and 136 are opposed to each other, and arespaced about 180° apart. Nozzles 134 and 135 are adjacent to each otherwith an acute angle therebetween, as is the case with nozzle 135 and136; nozzle 136 and 137; and nozzle 137 and 134.

Each of nozzles 134, 135, 136, and 137 has four open slots 141, 142, 143and 144, respectively. Each of the respective slots is arranged adjacentto each other, but oriented away from remaining portions of the otherrespective nozzles. For example, slots 141 are arranged in the 12o'clock to 3 o'clock position of nozzle 134 and are pointed away fromnozzles 135, 136, and 137. Slots 144 are arranged in the 3 o'clock to 6o'clock position of nozzle 137 and are oriented away from nozzles 134,136, and 135. Slots 143 are arranged in the 6 o'clock to 9 o'clockposition of nozzle 134 and are oriented away from nozzles 134, 135, and137. Slots 142 are arranged in the 9 o'clock to 12 o'clock position ofnozzle 134 and are oriented away from nozzles 134, 136, and 137.

The nozzle arrangement 84 of FIGS. 12 and 13 is used to generate agenerally rectangular shaped pulse. A generally rectangle shapedaperture is shown at 146 in FIGS. 13 and 18. The aperture 146 hasrounded corners, but is otherwise generally rectangular in shape.

FIGS. 14 and 15 show another embodiment of a nozzle arrangement 84. Inthis embodiment, the nozzle arrangement 84 is a single nozzle 150. Thenozzle 150 includes four open slots 152. The slots 152 are evenly spacedabout the circumference of the nozzle 150, about 90° from each other. Assuch, the slots 152 are located at the 12 o'clock, 3 o'clock, 6 o'clock,and 9 o'clock positions. The nozzle 150 generates a generally squareshaped pulse for filling a generally square shaped aperture 154. Theaperture 154 has rounded corners, but is otherwise square shaped.

FIG. 19 is a perspective view of an alternate embodiment of a nozzle170. Nozzle 170 has a tubular wall 172 which is obstruction-free, butunlike the above embodiments, tubular wall 172 in FIG. 19 isnon-cylindrical. In the specific illustration of FIG. 19, wall 172 islobed. In the embodiment shown, wall 172 includes a plurality of lobes174, embodied as curved or rounded projections 176. Four lobes 174 areshown in FIG. 19, but depending on the desired pulse shape, more or lesscould be used. A plurality of slots 178 are defined by the wall 172, inthis embodiment, symmetrically spaced about a center. The nozzle 170 isuseable to generate a rectangular-shaped pulse that will fill theaperture 146 as shown in FIGS. 13 and 18 and the aperture 154 of FIG.14.

It should be realized, that from the structures and arrangementdescribed above, a method of cleaning a filter element can be utilized.The method includes directing a jet of pressurized gas from a nozzle,such as any of the various nozzle arrangements 84 illustrated above,into a non-round tubesheet aperture. The jet of pressurized gas willhave a non-round, cross-sectional shape that is a same general shape asthe non-round opening in the tubesheet. The nozzle used in the nozzlearrangement 84 will have a channel for the pressurized gas that isobstruction-free.

The method can include directing the jet having an oval cross-sectioninto an oval-shaped opening, in a tubesheet. The step of directing thejet having an oval cross-section can include directing a jet ofpressurized gas from not more than a single nozzle, the nozzle beingtubular and defining at least two open slots. The step of directing caninclude directing a jet of pressurized gas from a tubular nozzledefining at least four open slots. Alternatively, the nozzle arrangementcan include at least two nozzles, with each nozzle defining at least twoopen slots.

The step of directing can include directing a jet having a triangularcross-section into a generally triangular-shaped opening in a tubesheet.The step of directing can include directing a jet of pressurized gasfrom at least three nozzles, each of the nozzles being tubular and eachnozzle defining no more than a single open slot. Alternatively, the stepof directing can include directing a jet of pressurized gas from no morethan a single nozzle, the nozzle being tubular and defining at leastthree open slots.

The step of directing can including directing a jet of having arectangular cross-section into a generally rectangular-shaped opening ina tubesheet. The step of directing can including directing a jet ofpressurized gas from at least four nozzles, each of the nozzles beingtubular and each having at least three open slots. Alternatively, thestep of directing can include directing a jet of pressurized gas from nomore than a single nozzle, the nozzle being tubular and defining atleast four open slots.

A method of designing a nozzle arrangement for directing a jet ofpressurized gas for cleaning the filter element can be implemented usingprinciples described above. The filter element can be: (i) tubular witha non-round cross-section; (ii) a panel filter element with a non-roundface; (iii) a V-pack; (iv) a mini V-pack; (v) an envelope bag; or (vi)any filter that covers the non-round opening of the tubesheet. Themethod will include designing a nozzle arrangement to generate a jet ofpressurized gas having a cross-sectional shape that is a same generalshape as the non-round opening in the tubesheet. The nozzle arrangementwill include at least one nozzle. Each nozzle has an unobstructed flowchannel. Each nozzle is tubular in shape and has at least one open slot.The step of designing can include designing a nozzle arrangement togenerate a jet of pressurized gas having, for example, an ovalcross-sectional shape. The step of designing can include designing anozzle arrangement to generate a jet of pressurized gas having across-sectional shape selected from the group consisting of oval,triangular, and rectangular (including square) to match arespectively-shaped: (i) filter element interior cross-section; or (ii)face of a panel filter element.

I claim:
 1. A nozzle arrangement for directing a jet of pressurized gasinto an aperture in a tube sheet holding a filter element; the nozzlearrangement comprising: (a) a tubular wall having an unobstructed flowchannel; (b) the tubular wall having a free end defining an opening incommunication with the unobstructed flow channel, and (c) the tubularwall further having at least two open slots extending from the free endalong the tubular wall and closed in board from the free end.
 2. Thenozzle arrangement of claim 1 wherein the tubular wall is cylindrical.3. The nozzle arrangement of claim 1 wherein the tubular wall includesthree open slots.
 4. The nozzle arrangement of claim 3 wherein the threeopen slots are evenly circumferentially spaced apart.
 5. The nozzlearrangement of claim 4 wherein the free end of the tubular wall isgenerally circular.
 6. The nozzle arrangement of claim 3 wherein thereare no more than three open slots in the tubular wall.
 7. The nozzlearrangement of claim 6 wherein the tubular wall is cylindrical.
 8. Thenozzle arrangement of claim 1 wherein the tubular wall is lobed.
 9. Thenozzle arrangement of claim 1 wherein the tubular wall includes a firstpair of open slots and a second pair of open slots; the first pair andsecond pair opposing each other.
 10. The nozzle arrangement of claim 1wherein there are no more than two open slots in the tubular wall.